<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .outer {
            /* width: 500px; */
            width: 280px;
            background: #ccabab;
            border: 1px solid #000;
        }

        .box {
            width: 100px;
            height: 100px;
            background-color: #36a7c7;
            border: 1px solid #000;
            /* 加外边距 */
            margin: 10px;
            /* display: inline-block; */
            float: left;
        }

        /* .box1 {
            float: right;
        } */
        .box1 {
            height: 120px;
        }
    </style>
</head>

<body>
    <div class="outer">
        <div class="box box1">1</div>
        <div class="box box2">2</div>
        <div class="box box3">3</div>
    </div>
</body>

</html>